OptionWit

Free Option Price Calculator

Option Evaluation Board

See what your position could be worth at Monday's open, next week, or right before expiry. It reprices your option with Black-Scholes at future dates and stock prices.

Position 30 DTE

Model value now i$0.00
Delta i0.000
Gamma i0.0000
Theta /day i0.000
Vega /pt i0.000
Breakeven at expiry i$0.00
1σ expected move i
Hover a cell for the full scenario.
gain vs your price loss vs your price ◂ current spot · amber column = today within 1σ move

Values are Black-Scholes model estimates per share (multiply by 100 for one contract). They assume implied volatility stays at your input (plus any IV change you set). Dividends are modeled when you set a yield in the advanced inputs, and you can price on a calendar or trading-day basis. Real quotes will still differ with bid/ask spread, early-exercise premium on American options, and shifting IV. This is an educational tool, not trading advice.

How this calculator works

Enter your option's details: the current stock price, the strike, days to expiry, the implied volatility from your broker's option chain, and what you paid for it. OptionWit then reprices the option with the Black-Scholes model at every combination of future date (the columns) and stock price (the rows). Each cell shows the option's estimated value and your gain or loss versus the option's current price.

Each cell is a full repricing, not an extrapolation from today's Greeks. Delta and theta are snapshots. They hold up for small moves over short horizons, but they drift further from the truth for the big move next week you actually care about, because delta itself shifts as the stock moves (gamma) and decay speeds up as expiry nears. Recomputing the model at each date and price sidesteps that entirely.

This is different from the profit-at-expiry charts most brokers show. Those only tell you how the trade ends. Most options are closed before expiry, and in the meantime the price is pulled by three forces at once: the stock moving, time passing, and implied volatility changing. The projection board makes all three visible. Read down a column to see what a stock move is worth, read across a row to watch time decay eat the premium at a constant stock price, and use the IV change control to model a volatility shift on top.

Why option prices surprise people

The most common surprise in options trading: the stock goes up, and your call loses money anyway. It happens because a call is not a miniature share of stock. It's a bet with a countdown clock and a volatility component. If the stock rises slowly, the daily loss from time decay (theta) can outweigh the gain from the move (delta). And if you bought before an event like earnings, the collapse in implied volatility afterward, known as IV crush, can wipe out the gain from a correct directional call. Set the IV change control to −10 or −20 and watch the whole board sink: that's the crush, priced before you take the trade instead of after.

Frequently asked questions

What is IV crush?

Implied volatility rises when the market expects a big move, like before earnings or an FDA decision, and that inflates option prices. Once the event passes, that uncertainty deflates almost instantly, and option prices drop even if the stock moved your way. To preview it, set the IV change control to a negative number (−10 to −30 vol points is common for earnings) and compare the board before and after. Our IV crush guide walks through a full worked example.

Why does my option lose value when the stock doesn't move?

Time decay. An option's price includes extrinsic value, which is payment for the chance of a bigger move before expiry, and that chance shrinks every day. The theta number in the position panel is your current daily bill. Decay also accelerates as expiry approaches, which you can see by reading across any row of the table.

Are these real market prices?

No. They're Black-Scholes model estimates, and real quotes will differ. The model assumes European-style exercise and constant volatility, and ignores dividends unless you enter a yield. Real markets add bid/ask spreads, dividend adjustments, early-exercise premium on American options, and IV that shifts with price and time. Treat the board as a map of the terrain, not a quote.

What implied volatility number should I enter?

Use the IV shown on your broker's option chain for the specific contract you're evaluating, since it varies by strike and expiry. As rough context: broad index options often run 12–20%, large-cap single stocks 25–50%, and high-momentum names or pre-earnings contracts can exceed 100%.

What does "breakeven at expiry" mean?

The stock price at which, on expiry day, the option's intrinsic value equals what you paid. For a call it's strike plus premium; for a put, strike minus premium. Before expiry your true breakeven is closer to the current stock price, since the option still carries time value. That's another reason the projection board is more useful than an expiry-only view.

Does this work for puts as well as calls?

Yes. Toggle CALL/PUT in the position panel. The model, Greeks, breakeven, and the whole projection board update for the option type you pick.